Re: [PATCH] x86: kvm: Restrict X86_FEATURE_VMMCALL to x86_64 platform

From: tedheadster
Date: Tue Jul 31 2018 - 08:57:57 EST


>
> This shouldn't be necessary; for systems that don't have virtualization
> extensions, the comment explains why setting X86_FEATURE_VMMCALL is safe.
>
> But it is also wrong, because you can run a 32-bit kernel as a guest on
> a 64-bit processor, and then it should set X86_FEATURE_VMMCALL because
> the processor has the vmmcall instruction and not Intel's vmcall.
>

Paolo,
I'm running this on a bare metal machine (no virtualization) with a
32-bit AMD i486 class cpu. Should the feature be showing up in
/proc/cpuinfo under the 'flags' line? It does on my machine, and it
looked wrong to me.

- Matthew